NASASpaceFlight.com Forum
Robotic Spacecraft (Astronomy, Planetary, Earth, Solar/Heliophysics) => Space Science Coverage => Topic started by: Jet Black on 05/19/2017 10:04 am
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This one is just flashing up on the BBC at the moment.
http://www.bbc.co.uk/news/science-environment-39964904
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This one is just flashing up on the BBC at the moment.
http://www.bbc.co.uk/news/science-environment-39964904
I've taken your link and placed it in the existing Proposed Europa Missions thread where stuff like this is kept.
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Many presentations on the lander, as well as spacecraft, instruments, etc here
https://www.lpi.usra.edu/opag/meetings/archive/
Just go through the Agendas and find the lander presentations.
Edit: For example: https://www.lpi.usra.edu/opag/meetings/feb2020/presentations/Maize.pdf
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As we do not seem have to a Europa Lander thread, and yesterday was one of the 2020 Decadal Survey (https://forum.nasaspaceflight.com/index.php?topic=51500.0) presentation on the Europa Lander (and Enceladus Orbilander (https://forum.nasaspaceflight.com/index.php?topic=40583.msg2174233#msg2174233) ), this might be a good place to remind readers that the website https://europa.nasa.gov has a lot of info on the Europa Clipper (https://forum.nasaspaceflight.com/index.php?topic=47579.0) but also on the Lander (after some digging :) ) The Europa Lander study report from 2016 (https://europa.nasa.gov/system/downloadable_items/50_Europa_Lander_SDT_Report_2016.pdf) with all details and attached as well. Posting it (again?) as I never saw it in the past.
There was also a small movie on the Lander mechanical testbed OLAF (https://www.youtube.com/watch?v=BqhgJql1mOs) i.e. how to land on Europa without toppling over.
Some fun facts and pointers on bio-signatures, terrain navigations, et al will be put in the appropriate threads later.
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That 2016 study report has been updated. I don't know where the updated version is. But the 2016 one is out of date.
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That 2016 study report has been updated. I don't know where the updated version is. But the 2016 one is out of date.
That is good to know. Please note that one of the slides from the NAS presentation on Europa Lander last Friday pointed to this version (slide attached). A quick search (Google, JPL TRS) doesn't show an updated report but only some presentations at JPL. Hence, a pointer to a full, updated version would be appreciated.
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https://oceanworldslab.jpl.nasa.gov
and
https://oceanworldslab.jpl.nasa.gov/publications/
provide some great list with background research.
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From a presentation today at OPAG about cryobot technology for a future Europa Lander. Pay no attention to the timeline.
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How does any sort of Europa/Enceledus tunneling bot work when we cannot actually steralize anything completely.
Even the Perseverance sample collection tubes (cleanest things ever made by mankind) might have bacteria on/in them. Its a VERY low level amount of it, but its not 100% life free. They were measuring to a threashold of detection (must be below x number of particles). However, the number was not zero.
Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
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Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
I don't think that's the way they approach planetary protection.
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From a presentation today at OPAG about cryobot technology for a future Europa Lander. Pay no attention to the timeline.
One thing I've thought that might limit the depth a cryobot can travel is dust and rocks mixed in with the ice. The actual amount of this stuff in the ice might be small, but... as you melt the ice, it'll all accumulate on the bottom and eventually slow or stop progress. So how feasible a cryobot is must depend on the purity of the ice and the depth it needs to travel. Surely this is addressed in these concept papers, right?
EDIT: Found a reference to it: http://robotics.estec.esa.int/i-SAIRAS/isairas2001/papers/Paper_AM064.pdf
This section in particular is explaining what I was thinking:
7.1 Passive Testing
The cryobot drilling mechanism in ice has two
components, a passive drilling mode, and an active
drilling mode. In the passive drilling mode, a heated
nose piece is melting the ice in contact with it. The
melt-water is squeezed radially along a film to the
outer edge of the vessel. In the case of permeable firn
the water is flowing into the pore spaces. The method
is limited by the amount of heat that can be transferred
without overheating the heating element. In our test
case we reached a heat density of 21 W/cm2
. The
passive method has limits in dust or debris laden ice.
As the debris in front of the heated nose accumulates,
forming an insulating heat shield, the drilling speed is
drastically reduced.
7.2 Active Testing
In any environment where dirty ice is expected, an
active drilling mode is a necessity. This method uses a
vigorous jet of heated water from a nozzle in the center
of the nose piece. The water hits the ice and forms a
conical water filled cavity in front of the nozzle about
30 cm deep. The warm water rotates in a vortex
transferring its heat into ice, causing a phase change
before it flows past the outside cryobot walls to the
back from where it is recycled to the pump that drives
the water jet. This active jet stream also works in
debris laden ice because it stirs up the dust and
particulates and holds them in suspension. For that
reason an active jetting system can drill much deeper
that a passive system alone. This method does not
work well in permeable firn because the water for
recycling is lost.
We conducted a comprehensive testing program to
determine the optimal choice for the adjustable
parameters, such as power to the heating pads, nose
shapes, drilling nozzle sizes, water flow rate, water
temperature, drilling speed (See Table 1)(See Fig. 7).
For a given power supply of about 1 kW and a cryobot
diameter of 12 cm, we obtain a drilling speed of 0.2
(Europa) to 0.8m/hr (Earth), depending on the ice
temperature. The drilling efficiency is 80-90% defined
by the ratio of maximum attainable drilling speed for
ideal borehole diameter to the actual drilling speed.
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How does any sort of Europa/Enceledus tunneling bot work when we cannot actually steralize anything completely.
Even the Perseverance sample collection tubes (cleanest things ever made by mankind) might have bacteria on/in them. Its a VERY low level amount of it, but its not 100% life free. They were measuring to a threashold of detection (must be below x number of particles). However, the number was not zero.
Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
"Complete sterilization" is not a requirement. You should look up COSPAR's planetary protection guidelines, which NASA has largely adopted. The requirements are specified in it.
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Well, put a chunk of Cobalt-60 in there, and you solve two problems: sterilization and heat production.
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One thing I've thought that might limit the depth a cryobot can travel is dust and rocks mixed in with the ice. The actual amount of this stuff in the ice might be small, but... as you melt the ice, it'll all accumulate on the bottom and eventually slow or stop progress. So how feasible a cryobot is must depend on the purity of the ice and the depth it needs to travel. Surely this is addressed in these concept papers, right?
During the discussion the presenter mentioned that they are considering things like what happens if it hits a pocket of salt or dust. Considering that it is supposed to melt through ice, that could be a big impediment.
I really don't know how much confidence anybody can ever have in these things. We've been studying penetrator probes for decades, and we still can't get them to work. This is even more difficult.
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How does any sort of Europa/Enceledus tunneling bot work when we cannot actually steralize anything completely.
Even the Perseverance sample collection tubes (cleanest things ever made by mankind) might have bacteria on/in them. Its a VERY low level amount of it, but its not 100% life free. They were measuring to a threashold of detection (must be below x number of particles). However, the number was not zero.
Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
"Complete sterilization" is not a requirement. You should look up COSPAR's planetary protection guidelines, which NASA has largely adopted. The requirements are specified in it.
Thats my point. They have set a requirement. For mars that is good enough. However, for a warm watery place, the current COSPAR requirements are not good enough. Not even close. Any mission we do right now would have a 100% chance of contaminating enceladus/europa with earth life.
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One thing I've thought that might limit the depth a cryobot can travel is dust and rocks mixed in with the ice. The actual amount of this stuff in the ice might be small, but... as you melt the ice, it'll all accumulate on the bottom and eventually slow or stop progress. So how feasible a cryobot is must depend on the purity of the ice and the depth it needs to travel. Surely this is addressed in these concept papers, right?
During the discussion the presenter mentioned that they are considering things like what happens if it hits a pocket of salt or dust. Considering that it is supposed to melt through ice, that could be a big impediment.
I really don't know how much confidence anybody can ever have in these things. We've been studying penetrator probes for decades, and we still can't get them to work. This is even more difficult.
It seems like the first thing to know before sending a penetrator is how thick the ice is above any subsurface ocean. Is Europa Clipper going to give use any idea of that figure? Will it be able to give us an estimate from surface images or some other way how pure the ice is from inclusions like salt or dust pockets?
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If Juice doesn’t get its antenna deployed, how will ice measurements be affected?
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If Juice doesn’t get its antenna deployed, how will ice measurements be affected?
Surface ice measurements by the passive remote sensing instruments wouldn't be affected.
Presumably, subsurface profiles either wouldn't be possible or would be compromised without the fully deployed ice penetrating radar antenna.
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How does any sort of Europa/Enceledus tunneling bot work when we cannot actually steralize anything completely.
Even the Perseverance sample collection tubes (cleanest things ever made by mankind) might have bacteria on/in them. Its a VERY low level amount of it, but its not 100% life free. They were measuring to a threashold of detection (must be below x number of particles). However, the number was not zero.
Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
"Complete sterilization" is not a requirement. You should look up COSPAR's planetary protection guidelines, which NASA has largely adopted. The requirements are specified in it.
Thats my point. They have set a requirement. For mars that is good enough. However, for a warm watery place, the current COSPAR requirements are not good enough. Not even close. Any mission we do right now would have a 100% chance of contaminating enceladus/europa with earth life.
Wrong. By several orders of magnitude.
In an analogous way that you're not getting a disease by catching a single virus, you're not even remotely close to 100% chance here.
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Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
"Complete sterilization" is not a requirement. You should look up COSPAR's planetary protection guidelines, which NASA has largely adopted. The requirements are specified in it.
Thats my point. They have set a requirement. For mars that is good enough. However, for a warm watery place, the current COSPAR requirements are not good enough. Not even close. Any mission we do right now would have a 100% chance of contaminating enceladus/europa with earth life.
Wrong. By several orders of magnitude.
In an analogous way that you're not getting a disease by catching a single virus, you're not even remotely close to 100% chance here.
Check out this article One Virus Particle Is Enough To Cause Infectious Disease (https://www.sciencedaily.com/releases/2009/03/090313150254.htm) for a contrasting opinion. It's not 100% sure by any means, but it appears to be possible.
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How does any sort of Europa/Enceledus tunneling bot work when we cannot actually steralize anything completely.
Even the Perseverance sample collection tubes (cleanest things ever made by mankind) might have bacteria on/in them. Its a VERY low level amount of it, but its not 100% life free. They were measuring to a threashold of detection (must be below x number of particles). However, the number was not zero.
Drilling into water under an moon would require a 100% clean device. A single bacteria getting in would be enough to contaminate the entire moon.
"Complete sterilization" is not a requirement. You should look up COSPAR's planetary protection guidelines, which NASA has largely adopted. The requirements are specified in it.
Thats my point. They have set a requirement. For mars that is good enough. However, for a warm watery place, the current COSPAR requirements are not good enough. Not even close. Any mission we do right now would have a 100% chance of contaminating enceladus/europa with earth life.
Wrong. By several orders of magnitude.
In an analogous way that you're not getting a disease by catching a single virus, you're not even remotely close to 100% chance here.
You cannot compare infectious dose for a disease with contaimination. They are vastly different things. A living creature has an immune system, so it takes a certain threshold amount of bacteria/viruses/ect to establish.
For example, a single mold spore is all thats needed to start a mold colony, because there isn't an immune system destroying the mold.